I just received DNA test results for my Maternal Haplogroup. It states that I am Haplogroup U. However, Haplogroup U has many sub-groups and my results don't show any sub-group link, just "U." Does this mean my sub-group could not be determined? Many of the Ancestry.com participants I am linked to show that they are Group U-5. Does that mean that U-5 may be my sub-group? Or is "U" as defined as it gets for me?